Durometer

ABSTRACT

An object of the present invention is to provide a durometer enabling a contact portion in contact with an object to perform smooth piston motion. The durometer includes a main body unit including a movable unit pressed continuously against an object to be measured, a first sensor outputting acceleration information corresponding to an acceleration of movement of a contact part of the object to be measured in contact with the movable unit in a pressing direction, a second sensor outputting reactive force information corresponding to a reactive force at the contact part of the object to be measured in contact with the movable unit, a motor, a crank mechanism driven by the motor and causing the main body unit and the movable unit to perform piston motion, and at least one buffering member disposed on a periphery of the main body unit.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.16/806,657 filed on Mar. 2, 2020 which claims priority to U.S. patentapplication Ser. No. 15/737,543, filed on Dec. 18, 2017, which claimsthe benefit of PCT/JP2016/061231 filed on Apr. 6, 2016, JP PatentApplication No. 2015-210979 filed on Oct. 27, 2015 and JP PatentApplication No. 2015-128007 filed on Jun. 25, 2015 which areincorporated by reference as if fully set forth.

TECHNICAL FIELD

The present invention relates to a durometer.

BACKGROUND ART

Conventionally, measuring hardness of an object has been useful in manycases. When an object is a human body, measuring hardness of the humanbody is useful in the medical field or the fields of dermatologicalsurgery and cosmetic surgery. For example, in the medical field,measuring the hardness of a given part allows for a medical diagnosissuch as ulcers on the skin surface of a bed-ridden patient who hassuffered from an ulcer as a result of having been in bed in the sameposition for a long period, skin edema caused by a change of an internalorgan, scleroderma, and so forth. Also, in the fields of dermatologicalsurgery and cosmetic surgery, measuring the hardness of a given partmakes it possible to determine progress of a disease and an effect of adrug therapy.

For example, a conventional tactile sensor, which acquires informationon a change in a resonance state caused when a mechanical vibration partcomes in contact with an object and which outputs the acquiredinformation as hardness information of the object, has been known (seePatent Document 1).

Further, a conventional technique for reciprocating a piston by use of acrank mechanism (see Patent Document 2) has been known, and aconventional technique for sealing a piston assembly (see PatentDocument 3) has also been known.

RELATED ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Patent Application Laid-Open Publication No.H10-062328

Patent Document 2: Japanese Patent Application Laid-Open Publication No.2012-154260

Patent Document 3: Japanese Patent Application Laid-Open Publication No.2003-156146

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

For example, it is assumed that information from an acceleration sensoris used in a durometer measuring hardness of an object. When theacceleration sensor is used, it is required to make a contact portion incontact with the object perform smooth piston motion such that noise isnot mixed in the information acquired from the sensor.

A technique of Patent Document 1 utilizes information on a change in theresonance state caused when the mechanical vibration part comes incontact with the object and in the first place, is not a techniqueutilizing the acceleration sensor. Accordingly, the durometer in whichthe acceleration sensor is used needs a configuration in which thecontact portion in contact with the object performs smooth pistonmotion.

Patent Document 2 discloses a technique by which piston motion isperformed by use of the crank mechanism. According to such a technique,movement of a crack shaft eccentric to a shaft of a power unit (motor,etc.) is converted into piston motion. As a result, the contact portionin contact with the object shakes laterally. This shaking motion causesnoise to be mixed in the information from the acceleration sensor. Forthis reason, it has been considered that applying the crack mechanism tothe durometer in which the acceleration sensor is used is difficult.

Also, Patent Document 3 discloses a technique by which the piston issealed. In this technique, only reduction in mechanical load applied toa tip portion of the piston has been taken into consideration. Thus, asealing technique enabling smooth piston motion in the durometer inwhich the acceleration sensor is used has not been studied so far.

In this regard, an object of the present invention is to provide adurometer enabling a contact portion in contact with an object toperform smooth piston motion.

Means for Solving the Problems

For example, in order to solve the above problems, configurationsdescribed in Claims are adopted. The present application includes aplurality of means solving the above problems, and by way of example,there is provided a durometer including a main body unit including amovable unit pressed continuously against an object to be measured, afirst sensor outputting acceleration information corresponding to anacceleration of movement of a contact part of the object to be measuredin contact with the movable unit in a pressing direction, a secondsensor outputting reactive force information corresponding to a reactiveforce at the contact part of the object to be measured in contact withthe movable unit, a motor, a crank mechanism driven by the motor andcausing the main body unit and the movable unit to perform pistonmotion, and at least one buffering member disposed on a periphery of themain body unit.

Also, according to another example, there is provided a durometerincluding a main body unit including a movable unit pressed continuouslyagainst an object to be measured, a first sensor outputting accelerationinformation corresponding to an acceleration of movement of a contactpart of the object to be measured in contact with the movable unit in apressing direction, a second sensor outputting reactive forceinformation corresponding to a reactive force at the contact part of theobject to be measured in contact with the movable unit, a motor, a crankmechanism driven by the motor and causing the main body unit and themovable unit to perform piston motion, at least one buffering memberdisposed on a periphery of the main body unit, and a contact memberencircling a periphery of the movable member and in contact with theobject to be measured, the contact member including a cutout.

Also, according to still another example, there is provided a contactmember for a durometer including a movable unit pressed continuouslyagainst an object to be measured. The contact member is configured insuch a way as to encircle a periphery of the movable unit and come incontact with the object to be measured, and includes a cutout.

Effects of the Invention

According to the present invention, in a durometer, a contact portion incontact with an object can perform smooth piston motion. Furthercharacteristics of the present invention will be apparent from thedescription of the present specification and the accompanying drawings.Also, other problems, configurations, and advantageous effects will beapparent from the description of the following embodiments.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is an overall configuration diagram of a biometric durometeraccording to an embodiment;

FIG. 2 is an explanatory diagram of an operation principle of ameasurement apparatus;

FIG. 3 is a schematic view of an example of a structure of themeasurement apparatus;

FIG. 4 is a graph indicating a relation between output voltage from areceiving coil and pressure caused by a pressing force;

FIG. 5 shows waveform diagrams corresponding to when an object is aspring, where (a) indicates output from an acceleration sensor, (b)indicates output from a magnetic sensor, (c) indicates output from apressure sensor, and (d) indicates output from a displacement sensor;

FIG. 6 shows waveform diagrams corresponding to calculation of hardness,where (a) indicates voltage from the magnetic sensor, (b1) indicates asecond-order differential waveform, (b2) indicates an accelerationwaveform based on output from the acceleration sensor, and (c) is awaveform diagram indicating displacement of the object;

FIG. 7 is an example of a flowchart illustrating the overall flow of aprocessing by the biometric durometer;

FIG. 8 is a configuration diagram of a biometric durometer according toa first embodiment;

FIG. 9 is a top view of a bearing member and a crank shaft in themeasurement apparatus;

FIG. 10 is a side view of a buffering member according to the firstembodiment;

FIG. 11 is a diagram of the buffering member according to the firstembodiment, when seen from a front side of the moving direction ofpiston motion;

FIG. 12 is a cross-sectional view taken along a line A-A of FIG. 11;

FIG. 13 is an example of preferred arrangement of the buffering membersof the first embodiment;

FIG. 14 is an enlarged view illustrating another configuration of thebiometric durometer according to the first embodiment;

FIG. 15 is a diagram of a contact member according to the firstembodiment, when seen from the front side of the moving direction of thepiston motion;

FIG. 16 is a side view of the contact member according to the firstembodiment;

FIG. 17 is a configuration diagram of a biometric durometer according toa second embodiment;

FIG. 18 is a side view of another example of the buffering member;

FIG. 19 is a diagram of the buffering member of FIG. 18, when seen fromthe front side of the moving direction of the piston motion;

FIG. 20 is a diagram of another example of the buffering member, whenseen from the front side of the moving direction of the piston motion;and

FIG. 21 is a cross-sectional view when the buffering member of FIG. 20is disposed in the measurement apparatus.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings. Note that specific embodiments according tothe principle of the present invention are illustrated in theaccompanying drawings, but these are provided for the purpose ofunderstanding the present invention and not used to interpret thepresent invention in a limited way. Also, the common configurations ineach of the drawings may be denoted by the same reference characters. Inthe following description, different units, such as V (bolt) and mV(millimeter volt), may be adopted for convenience of description orillustration.

The following embodiments relate to a technique for calculating hardnessof an object to be measured. In the following description, a living bodysuch as human body is taken as an example of the object to be measured.The object to be measured is, however, not limited to the living body.For example, a durometer according to the following embodiments may beapplied also to an object other than the living body.

Hardness is an index indicating how hard an object to be measured is.Hardness can be indicated as various types of indexes. By way ofexample, hardness may be defined by a conception including at leasteither elasticity or viscosity. Elasticity represents such a propertythat the object deformed by an applied force tries to return to itsoriginal state when the force is removed. Viscosity represents such aproperty that the object deformed by an applied force is hard to returnto its original state.

FIG. 1 is an overall configuration diagram of a biometric durometer. Abiometric durometer 1000 includes a measurement apparatus 1 and ahardness calculation apparatus 2. Note that parts of the configurationare omitted in the measurement apparatus 1 in FIG. 1, compared to themeasurement apparatus 1 in each of FIGS. 2 and 3.

The configuration and an operation principle of the measurementapparatus 1 will be described, referring to FIG. 1 as well as FIGS. 2and 3. The measurement apparatus 1 includes a main body unit 14 having areceiving coil 11 (magnetic field detecting means), a movable unit 15having a transmitting coil 12 (magnetic field generating means) and anacceleration sensor 13, and a spring 16 (resilient member). Note that acombination of the receiving coil 11 and the transmitting coil 12 isreferred to as a magnetic sensor 19. The magnetic sensor 19 outputsreactive force information corresponding to a reactive force generatedat a contact part of the object in contact with the movable unit 15. Theacceleration sensor 13 outputs acceleration information corresponding tothe acceleration of movement of the movable unit 15 in a pressingdirection at the contact part of the object in contact with the movableunit 15.

A contact portion 20 of the movable unit 15 is a portion pressed againsta trunk B of a human body, which is the object, in such a way as to dentthe trunk B at hardness calculation. Note that the main body unit 14 andthe movable unit 15 have rigidity. The acceleration sensor 13 detectsinformation of the acceleration of the movement in the pressingdirection. The trunk B has a spring-like property and a dashpot-likeproperty. For example, it is assumed that the trunk B has a spring 17(a) (spring constant K) and a dashpot 17 (b) (dashpot constant G). Thespring constant K corresponds to an elasticity component of the trunk B,and the dashpot constant G corresponds to a viscosity component of thetrunk B. At least one of the elasticity component and the viscositycomponent is a subject of calculation carried out in this embodiment.

The magnetic sensor 19 outputs information of a voltage corresponding toa magnitude of the reactive force of the trunk B in response to apressure applied to the trunk B by the measurement apparatus 1. To allowthe magnetic sensor 19 to function in this manner, the receiving coil 11and the transmitting coil 12 are disposed to be opposed to each other.Also, the spring 16 with a (known) spring constant K′ is disposedbetween the main body unit 14 and the movable unit 15 (see FIG. 2). Notethat the spring 16 should be selected such that a relation K′>K issatisfied. Otherwise, when a pressing force F is applied to the mainbody unit 14 (see FIG. 2), the main body unit 14 and the movable unit 15come in contact with each other at the contact portion 20, and as aresult, the function of the magnetic sensor 19 is impaired. For example,the measurement apparatus 1 may be designed such that a distance Dbetween the main body unit 14 and the movable unit 15 is substantially 2mm and a compression amount of the spring 16 is substantially 0.5 mmwhen the pressing force F is applied to the main body unit 14.

The spring 16 may be replaced with a spring having the same shape and alarger wire diameter. Also, a free length of the spring 16 may beincreased. When the spring 16 having such a configuration is adopted, alarger pressing force F is needed to cause the spring 16 to becompressed by the same amount of compression. As a result, a largerforce is applied to the object from the main body unit 14. Accordingly,hardness of a part in a deep layer of the object can be measured.Conventionally, hardness has been measured only at the skin surface, andthis poses a problem that information on a deeper layer of the skincannot be acquired. In contrast, the above configuration enablesmeasurement of not only the hardness of the skin surface but also thehardness in a range from the skin surface to the subcutaneous tissue,the muscle, etc., in the deeper layer of the skin.

Then, operations of the magnetic sensor 19 and peripheral componentsaround the magnetic sensor 19 will be described with reference to FIG.2. First, an AC oscillation source 31 generates an AC voltage having aspecific frequency (e.g., 20 kHz). The generated AC voltage is convertedby an amplifier 32 into an AC current having a specific frequency, andthe converted AC current flows through the transmitting coil 12. The ACcurrent flowing through the oscillation coil 12 generates a magneticfield, which generates an induced electromotive force at the receivingcoil 11.

The induced electromotive force generates an AC current (with the samefrequency as the frequency of the AC voltage generated by the ACoscillation source 31) at the receiving coil 11. The generated ACcurrent is amplified by a preamplifier 33, and a signal after theamplification is input to a detection circuit 34. The detection circuit34 detects the signal after the amplification using the specificfrequency or a double frequency of the specific frequency generated bythe AC oscillation source 31. For the detection, an output from the ACoscillation source 31 is introduced into a reference signal inputterminal of the detection circuit 34 as a reference signal 35. Anoperation method using a full-wave rectifier circuit instead of usingthe detection circuit 34 may be employed. Voltage information (outputsignal) from the detection circuit 34 (or the rectifier circuit) passesthrough a low-pass filter 36 and is introduced to a driving circuit 21(see FIG. 1) of the hardness calculation apparatus 2.

Note that the relation between the pressure (force F) applied to themain body unit 14 and a magnitude of the voltage expressed by the outputsignal introduced from the low-pass filter 36 to the driving circuit 21is as illustrated by a line 4 a (broken line) in FIG. 4. The line 4 aextends linearly because the spring constant K′ of the spring 16 islarge and the amount of compression of the spring 16 in response to thepressure to the main body unit 14 is small. Even if a relation betweenthe pressure (force F) and the output signal introduced to the drivingcircuit 21 is not proportional, such a relation is converted so as tohave a linear characteristic, and the linear relation illustrated inFIG. 4 is calculated. By correcting the line 4 a to a line 4 b (solidline) such that the voltage becomes zero when the pressure is zero, therelation between the pressure and the voltage may have a proportionalrelation passing through an origin. The above correction can be carriedout by, for example, a microprocessor 23, which will be described later.Also, a conversion coefficient indicating a ratio of the pressureapplied to the trunk B to the voltage information output by the magneticsensor 19 will hereinafter be referred to as voltage/pressure conversioncoefficient (C_(mp) [N/mV]), which is experimentally calculated inadvance.

Then, the hardness calculation apparatus 2 will be described, referringback to FIG. 1. The hardness calculation apparatus 2 is a computerapparatus. The hardness calculation apparatus 2 includes drivingcircuits 21 and 22, the microprocessor 23, a storage unit 24, a soundgeneration unit 25, a display unit 26, a power source unit 27, and aninput unit 28.

The driving circuit 21 receives voltage information sent from thereceiving coil 11 of the measurement apparatus 1 through the low-passfilter 36 (see FIG. 2), etc., and transmits the voltage information tothe microprocessor 23. The driving circuit 22 receives accelerationinformation sent from the acceleration sensor 13 of the measurementapparatus 1, and transmits the acceleration information to themicroprocessor 23.

The microprocessor 23 is realized by, for example, a CPU (CentralProcessing Unit). The microprocessor 23 includes a differential waveformgeneration unit 231, a waveform comparison unit 232, a conversioncoefficient calculation unit 233, a calculation unit 235, and adetermination unit 236. These processing units of the microprocessor 23can be realized by various programs. For example, various programsstored in the storage unit 24 are loaded into a memory (not illustrated)of the hardness calculation apparatus 2. The microprocessor 23 executesa program loaded into the memory. Processing contents executed by theprocessing units of the microprocessor 23 will be described below withreference to FIGS. 5 and 6.

As illustrated in FIG. 5, when a spring with a spring constant of 0.935kgf/mm is used, an output of the acceleration sensor 13 is as indicatedin (a), an output of the magnetic sensor 19 is as indicated in (b), anoutput of a pressure sensor (not illustrated) used in place of themagnetic sensor 19 is as indicated in (c), and an output (true value(correct value) of displacement) of a displacement sensor (notillustrated) such as a laser sensor is, as a reference, as indicated in(d).

An object of the present embodiment is to calculate the hardness of theobject, that is, to calculate at least one of the spring constant K andthe dashpot constant G in FIG. 2. To achieve this, it is first necessaryto acquire information as close as possible to output informationindicated in (d) by using at least one of pieces of output informationindicated in (a), (b), and (c) of FIG. 5. Then, the hardness of theobject is calculated by using the acquired information.

In other words, to calculate the hardness characteristics of the objectwithout using a displacement sensor such as a laser sensor, informationprovided by the acceleration sensor 13 and the magnetic sensor 19 (orpressure sensor) is used. Reasons that the displacement sensor is notused are, for example, that using the displacement sensor is difficultin some circumstances, depending on surface condition of the object orwhether the sensor can be fixed to the object, and that the displacementsensor is expensive.

In FIG. 5, comparing the waveform of the output from the magnetic sensor19 indicated in (b) with the waveform of the output from thedisplacement sensor indicated in (d), both waveforms are different inunit on the vertical axis and amplitude, while they are similar in shapeand are identical in frequency. Accordingly, by multiplying the waveformof the output from the magnetic sensor 19 indicated in (b) by a givenconversion coefficient (which will hereinafter be referred to as“voltage/displacement conversion coefficient (C_(md) [mm/mV])”),information of a waveform approximate to the waveform of the output fromthe displacement sensor indicated in (d) can be obtained. Thevoltage/displacement conversion coefficient C_(md) is a numerical valueindicating a ratio of a magnitude of an acceleration waveform to amagnitude of a second-order differential waveform (which will bedescribed in detail later). Note that this process of approximation issimilarly applicable to the waveform of the output from the pressuresensor indicated in (c) with respect to the waveform of the output fromthe displacement sensor indicated in (d).

Here, calculation of the hardness of the object will be described usingmathematical formulas (see the drawings as needed). When the amount ofcompression (amount of displacement) of the spring 17 (a) and thedashpot 17 (b) caused by the pressing force (pressure) F applied to themain body unit 14 is denoted as X (see FIG. 2) and an output voltagefrom the magnetic sensor 19 is denoted as V_(m), the following equations(1), (2), and (3) are established. Note that, as a result of the law ofaction and reaction, the force (pressure) F is applied also to thecontact portion 20 between the movable unit 15 and the trunk B.

[Mathematical Formula 1]

F=K×X  Equation (1)

X=C _(md) ×V _(m)  Equation (2)

F=C _(mp) ×V _(m)  Equation (3)

Equation (1) is an equation representing the Hooke's law. Equation (2)is an equation indicating that the amount of displacement X can beobtained by multiplying the output voltage V_(m) from the magneticsensor 19 by the voltage/displacement conversion coefficient C_(md).Equation (3) is an equation indicating that the pressure F can beobtained by multiplying the output voltage V_(m) from the magneticsensor 19 by a voltage/pressure conversion coefficient C_(mp).

Then, substituting Equations (2) and (3) for Equation (1) andsimplifying the resulting equation yields the following Equation (4).

[Mathematical  Formula  2]                              $\begin{matrix}{K = \frac{C_{mp}}{C_{md}}} & {{Equation}\mspace{14mu}(4)}\end{matrix}$

Equation (4) indicates that a complex elastic modulus of the object canbe calculated by dividing the voltage/pressure conversion coefficientC_(mp) by the voltage/displacement conversion coefficient C_(md). Inthis embodiment, this complex elastic modulus is used as information onthe hardness.

Referring back to FIG. 1, the storage unit 24 is means storing variouspieces of information and is realized by, for example, a RAM (RandomAccess Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), etc.The storage unit 24 stores in advance the voltage/displacementconversion coefficient C_(mp) calculated through an experiment.

The sound generation unit 25 is means generating a sound and is realizedby, for example, a speaker. The sound generation unit 25 generates abeeping sound at the start and the end of measurement by the measurementapparatus 1, for example.

The display unit 26 is means displaying various data and is realized by,for example, an LCD (Liquid Crystal Display) or CRT (Cathode Ray Tube)display. The display unit 26 displays various waveforms, the hardness ofthe object (e.g., at least one of elasticity information and viscosityinformation), and an indicator visualizing the hardness of the object.

The power source unit 27 is power supply means in the hardnesscalculation apparatus 2. The input unit 28 is means operated by a userfor inputting various pieces of information and is realized by, forexample, a keyboard, a mouse, etc.

An example of a structure of the measurement apparatus 1 will bedescribed with reference to FIG. 3. Matters described with reference toFIG. 2 will be appropriately omitted. A measurement apparatus 1 a(1) isa pencil shape as a whole. The measurement apparatus 1 a(1) includes themain body unit 14 and the movable unit 15.

The main body unit 14 includes the receiving coil 11, a coil board 120having the receiving coil 11 mounted, an operating circuit board 130connected to the receiving coil 11 and the transmitting coil 12, abattery 18, an operation button 190 to be operated at the start ofhardness calculation, etc., and the display unit 26. The movable unit 15has the transmitting coil 12, the acceleration sensor 13, and a coilboard 110 having the transmitting coil 12 and the acceleration sensor 13mounted.

A spring 16 a (16) is disposed between the coil board 110 and the coilboard 120, and the number of the spring 16 a(16) is one, two, three, orfour. Ina simple mode, a single spring 16 a(16) can be used, and adiameter of the spring 16 a(16) is equal to or larger than a diameter ofeach coil of the coil board 110 and the transmitting coil 12. Theconfiguration in which the single spring 16 a(16) is used allows eachcoil of the coil board 110 and the transmitting coil 12 to be disposedinside the spring 16 a(16), thereby enabling miniaturization of themeasurement apparatus.

According to the measurement apparatus 1 a(1), when the movable unit 15is pressed against the object in such a way as to dent the object, thespring 16 a(16) is compressed to cause the transmitting coil 12 and thereceiving coil 11 to approach each other. This increases a magnitude ofa magnetic field detected by the receiving coil 11. As a result,information of a voltage corresponding to a magnitude of a reactiveforce generated at the contact portion 20 is output from the receivingcoil 11. Also, since the measurement apparatus 1 a(1) is a pencil shapeas a whole, it is compact and is easy to use.

Then, a process of the biometric durometer 1000 will be described withreference to a flowchart of FIG. 7 (see other drawings as needed).

First, an operator operates the operation button 190 of the measurementapparatus 1 (step S1). In this step, the whole of the measurementapparatus 1 a(1) is attached to a motor not illustrated. In thisconfiguration, by driving the motor, it is possible to press the movableunit 15 against the object continuously at a given frequency fHz.

The microprocessor 23 of the hardness calculation apparatus 2 acquiresinformation from the measurement apparatus 1 every time the movable unit15 of the measurement apparatus 1 is pressed against the object. Basedon the information (reactive force information and accelerationinformation) acquired from the measurement apparatus 1, themicroprocessor 23 calculates the hardness (e.g., complex elasticmodulus) (step S2). Then, the microprocessor 23 calculates an averagevalue and a variance of the hardness data calculated at step S2 (stepS3).

Subsequently, the microprocessor 23 determines whether the average valueand the variance calculated at step 3 are abnormal values (step 4). Thisprocess is executed by the determination unit 236 of the microprocessor23. When the determination is Yes, the process proceeds to step S5. Whenthe determination is No, the process proceeds to step S6. Note thatdetermination whether the average value and the variance are abnormalvalues can be made by comparing the average value and the variance witha present threshold, for example.

When the determination is Yes at step S4 (when the values are abnormal),the microprocessor 23 causes the display unit 26 to display a message ofremeasurement, and the process returns to step S2 (step S5).

When the determination is No at step S4, the microprocessor 23 causesthe display unit 26 to display information on the hardness (step S6),and the process ends. In this embodiment, the movable unit 15 of themeasurement apparatus 1 is pressed against the object a plurality oftimes, and accordingly, a plurality of pieces of information on thehardness can be acquired through the calculation at step S2. By way ofexample, the display unit 26 may display the average value ofinformation on the hardness and the average value of information on theelasticity component.

Then, the calculation of the hardness (step S2) will be described withreference to FIG. 6. An example of calculating the complex elasticmodulus as the hardness will be described below. Note that acquisitionof a plurality of pieces of information on the hardness has beendescribed in FIG. 7. In the following example, however, one round ofcalculation of the hardness will be described.

The microprocessor 23 acquires a voltage waveform based on voltageinformation sent from the magnetic sensor 19 through the driving circuit21, and an acceleration waveform based on acceleration information sentfrom the acceleration sensor 13 through the driving circuit 22. Thevoltage waveform is input to the differential waveform generation unit231. The acceleration waveform is input to the waveform comparison unit232. (a) of FIG. 6 indicates the voltage waveform. Also, (b2) of FIG. 6indicates the acceleration waveform.

Then, the differential waveform generation unit 231 differentiates thevoltage waveform twice to generate a second-order differential waveform.(b1) of FIG. 6 indicates the second-order differential waveformcalculated from the voltage waveform.

Subsequently, the waveform comparison unit 232 compares the second-orderdifferential waveform ((b1) of FIG. 6) calculated by the differentialwaveform generation unit 231 with the acceleration waveform ((b2) ofFIG. 6), and outputs the result of the comparison to the conversioncoefficient calculation unit 233. Base on the comparison result, theconversion coefficient calculation unit 233 calculates thevoltage/displacement conversion coefficient C_(md). The conversioncoefficient calculation unit 233 outputs the calculatedvoltage/displacement conversion coefficient C_(md) to the calculationunit 235.

Specifically, for example, the voltage/displacement conversioncoefficient C_(md) can be calculated by use of the following Equation(5) (see (b) of FIG. 6). Am and Aa in the equation (5) correspond to avoltage value and an acceleration value indicated in (b1) and (b2) ofFIG. 6, respectively.

[Mathematical  Formula  3]                              $\begin{matrix}{C_{md} = \sqrt{\frac{\Sigma_{t}A_{a}^{2}}{\Sigma_{t}A_{m}^{2}}}} & {{Equation}\mspace{14mu}(5)}\end{matrix}$

Subsequently, the calculation unit 235 divides the voltage/pressureconversion coefficient C_(mp) stored in the memory unit 24 in advance bythe voltage/displacement conversion coefficient C_(md) (see Equation(4)) to calculate the absolute value K of the complex elastic modulus ofthe object. The complex elastic modulus is a value of a dynamic physicalproperty of a material of an object to be measured, taken intoconsideration missing energy in the form of heat upon deforming andrecovering. The real part of the complex elastic modulus is equivalentto a storage modulus, and the imaginary part of the complex elasticmodulus is equivalent to a loss modulus.

In the above embodiment, an example in which the complex elastic modulusis calculated as the hardness has been described. Hardness calculationis, however, not limited to this example. In another example, at leastone piece of information of an elasticity component and a viscositycomponent may be calculated as more detailed information of thehardness. By way of example, a phase difference between the accelerationwaveform and the second-order differential waveform calculated from thevoltage waveform is calculated, and then, information of each of theelasticity component and the viscosity component may be calculated byuse of the complex elastic modulus and the phase difference.

Embodiments relating to a structure of the measurement apparatus 1 ofthe biometric durometer 1000 described above will hereinafter bedescribed.

First Embodiment

FIG. 8 is a configuration diagram of a biometric durometer according toa first embodiment. FIG. 8 mainly illustrates constituent elements ofthe measurement apparatus 1 and does not illustrate constituent elementsof the hardness calculation apparatus 2. The hardness calculationapparatus 2 may be incorporated into the measurement apparatus 1 of FIG.8 or may be realized by another computer apparatus connected to themeasurement apparatus 1 with or without a wire.

The measurement apparatus 1 includes a motor 81 and a crank mechanismdriven by the motor 81. The crank mechanism includes a crank shaft 82located eccentric to a shaft 81 a of the motor 81, and a link(connecting member) 84 connecting the crank shaft 82 to the main bodyunit 14. The measurement apparatus 1 is configured such that themeasurement apparatus 1 transmits power from the motor 81 to the mainbody unit 14 through the crank mechanism to press the movable unit 15against the object at a given frequency.

More specifically, the structure of the measurement apparatus 1 will bedescribed. The measurement apparatus 1 includes a housing 80 housingvarious constituent elements described below. In a plan view of FIG. 8,the housing 80 has a shape that is bent almost at a right angle. Thehousing 80 includes a first portion 80 a and a second portion 80 b. Thefirst portion 80 a has the motor 81 disposed therein, and the secondportion 80 b has the main body unit 14 disposed therein. In a bentportion between the first portion 80 a and the second portion 80 b ofthe housing 80, the crank mechanism is disposed. According to thisconfiguration, when the motor 81 disposed in the first portion 80 a isdriven, the crank mechanism enables the main body unit 14 and themovable unit 15 to perform piston motion.

Moreover, according to this configuration, the operator is able todirect the second portion 80 b at the object, holding the first portion80 a by hands. In this manner, the biometric durometer of the presentembodiment has the configuration which does not require the object to bemeasured to stand absolutely still and which is preferably applicable toan object to be measured with motion, such as human body.

The shaft 81 a of the motor 81 is attached to a cylindrical bearingmember 83. The crank shaft 82 is attached to the bearing member 83 at aposition eccentric to the shaft 81 a of the motor 81. FIG. 9 is a topview of the bearing member 83 and the crank shaft 82. Also, to furtherstabilize rotation of the shaft 81 a, the bearing member 83 may have abearing fixed around the shaft 81 a.

The crank shaft 82 is connected to the main body unit 14 via the link84. According to this configuration, when the motor 81 is driven, thecrank shaft 82 located eccentric to the shaft 81 a of the motor 81rotates around the shaft 81 a of the motor 81 in a plan view of FIG. 9.This rotation of the crank shaft 82 causes the link 84 to move in aright and left direction in FIG. 8, and as a result, the main body unit14 and the movable unit 15 perform the piston motion. In the followingdescription, a direction of the piston motion of the main body unit 14and the movable unit 15 is referred to as a moving direction.

Note that a length 11 of the link 84 is preferably ⅓ or more of a length12 of the main body unit 14 in the moving direction. In thisconfiguration, it is possible to reduce a lateral movement (rattling inthe housing 80) arising when the main body unit 14 and the movable unit15 perform the piston motion by the crank mechanism.

The main body unit 14 has a cylindrical shape. The main body unit 14includes a first member 86 connected to the link 84, and a second member87 connected to the first member 86. The first member 86 is connected tothe link 84 via a connecting member 85. The first member 86 has anextending portion 86 a extending inside the second member 87. Theextending portion 86 a includes the coil board 120 to which thereceiving coil 11 is attached. The coil board 120 is disposed at aposition opposed to the coil board 110 of the movable unit 15.

The second member 87 of the main body unit 14 has the movable unit 15.The movable unit 15 has a cylindrical shape. The movable unit 15includes a first member 91 having the contact portion 20 to be incontact with the object, and a second member 92 connected to the firstmember 91 and disposed inside the second member 87 of the main body unit14. The movable unit 15 is supported inside the second member 87 of themain body unit 14, with the contact portion 20 to be in contact with theobject projecting out of a front end of the second member 87.

The spring 16 is disposed between the first member 91 of the movableunit 15 and a projecting portion 87 a of the second member 87 of themain body unit 14. The second member 92 of the movable unit 15 includesthe coil board 110 to which the transmitting coil 12 is attached. Thecoil board 110 is disposed at a position opposed to the coil board 120.Accordingly, the receiving coil 11 and the transmitting coil 12 aredisposed so as to be opposed to each other. Also, the coil board 110 hasthe acceleration sensor 13 attached thereon.

As a characteristic of the present embodiment, a plurality of bufferingmembers 93 are disposed on a periphery of the main body unit 14. By wayof example, the buffering members 93 are rubber members. Each bufferingmember 93 is made of, for example, a silicone rubber. The bufferingmember 93 may be made of not a silicone rubber but a rubber used for apacking material, etc. In the example of FIG. 8, two buffering members93 are disposed between the main body unit 14 and the housing 80.According to this configuration, even if the lateral movement (rattlingin the housing 80) arises when the main body unit 14 and the movableunit 15 perform the piston motion by the crank mechanism, the bufferingmembers 93 disposed between the main body unit 14 and the housing 80 canprevent the main body unit 14 from coming in contact with the housing80. Preventing the main body unit 14 from coming in contact with thehousing 80 enables the main body unit 14 and the movable unit 15 toperform smooth piston motion. Accordingly, this prevents noise frommixing in the information from the acceleration sensor 13, and as aresult, accuracy of the hardness measured by the biometric durometer isimproved.

From the viewpoint of preventing the main body unit 14 from coming incontact with the housing 80, it is sufficient if the buffering members93 are disposed at least two places on the periphery of the main bodyunit 14. Also, the buffering member 93 may be disposed against a partwhere the main body unit 14 is expected to come in contact with thehousing 80.

FIGS. 10 to 12 each illustrate a structure of the buffering member 93.FIG. 10 is a side view of the buffering member 93, and FIG. 11 is adiagram of the buffering member 93, when seen from a front side of themoving direction of the piston motion. Also, FIG. 12 is across-sectional view taken along a line A-A of FIG. 11.

The buffering member 93 has a ring shape encircling the periphery of themain body unit 14 (FIG. 11). Also, the buffering member 93 has anS-shaped section (FIG. 12). This S-shaped section enables the bufferingmember 93 to have a spring property. Having the spring property, thebuffering member 93 always returns to its original position easily whenthe main body unit 14 performs the piston motion. Accordingly, it ispreferable that the buffering member 93 has the spring property in orderto perform the stable piston motion, while having a function ofpreventing the main body unit 14 from coming in contact with the housing80.

FIG. 13 is an example of preferred arrangement of the buffering members93. Two buffering members 93 are disposed such that their S-shapes faceeach other. In other words, the two buffering members 93 are disposedsuch that their S-shapes are symmetrical with each other with respect toa plane perpendicular to the moving direction (which is indicated by adotted line in FIG. 13). When the main body unit 14 performs the pistonmotion, positions of the buffering members 93 may be shifted in themoving direction. In this manner, when the buffering members 93 aredisposed such that their S-shapes face each other, it is possible toprevent the buffering member 93 from shifting when the main body unit 14performs the piston motion.

Note that, although the buffering member 93 with an S-shaped section hasbeen described in the example of FIGS. 10 to 13, the configuration ofthe buffering member 93, however, is not limited to this. The bufferingmember 93 may have a rectangular cross-sectional shape. When its springproperty is taken into consideration, the buffering member 93 may have across-sectional shape having at least one curved part.

To prevent the buffering members 93 from shifting when the piston motionis performed, the main body unit 14 may have an antislip member 94disposed on the periphery of the buffering members 93. By way ofexample, the antislip member 94 is a polyester tape (Mylar tape). It issufficient if the antislip member 94 serves as an element forming alevel difference on the main body unit 14, and the antislip member 94may be made of a material different from the polyester tape.

In the example of FIG. 8, the antislip member 94 is disposed between thetwo buffering members 93. The position of the antislip member 94 is,however, not limited to the position in this example. FIG. 14 is anenlarged view illustrating another configuration of the biometricdurometer. As illustrated in FIG. 14, preferably, the antislip member 94may be disposed in front of and behind each buffering member 93 in themoving direction.

Also, as illustrated in FIG. 14, the main body unit 14 may have grooveportions 96 provided at positions corresponding to the buffering members93. These groove portions 96 can prevent the buffering members 93 fromshifting when the main body unit 14 performs the piston motion.

Also, as illustrated in FIG. 14, the housing 80 may have groove portions95 provided at positions corresponding to the buffering members 93.These groove portions 95 can prevent the buffering members 93 fromshifting when the main body unit 14 performs the piston motion.

Also, according to the present embodiment, the measurement apparatus 1further includes a contact member (guard member) 101 encircling aperiphery of the movable unit 15 and coming in contact with the objectto be measured. The contact member 101 is cylindrical and is attached toa front end of the second portion 80 b of the housing 80 with a screw103.

The contact member 101 has a press portion 101 a pressed against theobject to be measured (FIG. 8). The relation between the press portion101 a of the contact member 101 and the contact portion 20 of themovable unit 15 will be described here. A surface of the contact portion20 of the movable unit 15 and a surface of the press portion 101 a ofthe contact member 101 are flush with each other when the surfaces areat the midpoint of the amplitude of the piston motion. At the peak ofthe amplitude of the piston motion, therefore, the surface of thecontact portion 20 of the movable unit 15 projects forward from thesurface of the press portion 101 a of the contact member 101. By way ofexample, when the amplitude of the piston motion is 3 mm, the surface ofthe contact portion 20 of the movable unit 15 projects by 1.5 mm forwardfrom the surfaces of the press portions 101 a of the contact member 101at the peak of the amplitude of the piston motion.

FIG. 15 is a diagram of a contact member 101, when seen from the frontside of the moving direction of the piston motion, and FIG. 16 is a sideview of the contact member 101. The contact member 101 has three pressportions 101 a. To form a single surface against the object to bemeasured, the contact member 101 needs to include at least three pressportions 101 a making up the single surface. According to thisconfiguration, when the three press portions 101 a are brought intocontact with the object to be measured and the main body unit 14performs the piston motion, the measurement apparatus 1 can be held at acertain position (height) relative to the object to be measured, and, atthe same time, the contact portion 20 of the movable unit 15 can bebrought into contact perpendicularly with the object to be measured. Asa result, accurate hardness information can be obtained.

Also, the contact member 101 has three cutouts 102. For example, whenthe object to be measured is a human body, pressing the contact member101 against the object to be measured causes skin surface to be hardeneddue to tension of the skin surface. When the skin surface becomes ahardened state in this manner, the original hardness of the skin or themuscle cannot be measured. In contrast, since the contact member 101 hasthe cutouts 102, the tension of the skin surface is released through thecutouts 102. Accordingly, the original hardness of the skin or themuscle can be measured.

Note that the number of cutouts 102 is not limited to three. Since thecutouts 102 serves the above mentioned function of releasing the tensionof the skin surface, the cutouts 102 should preferably be provided insuch a way as to occupy a wider area in the contact member 101. By wayof example, it is preferable that, in a plan view (of the contactsurface in contact with the object to be measured) in FIG. 15, thecutouts 102 occupy ½ or more of the circumference R of the contactmember 101.

Second Embodiment

FIG. 17 is a configuration diagram of a biometric durometer according toa second embodiment. The same constituent elements as described in theabove embodiment will be denoted by the same reference characters, andthe descriptions thereof are omitted.

A characteristic of the present embodiment is in that one bufferingmember 104 is disposed on the periphery of the main body unit 14. Thebuffering member 104 is disposed between the main body unit 14 and thehousing 80. The buffering member 104 is a gelled member covering theperiphery of the main body unit 14. For example, the buffering member104 is a silicone gel. Further, the buffering member 104 may be providedas a bag of silicone gel or material equivalent thereto. Note thatanother gelled member different from the silicone gel may be used as thebuffering member 104 from the viewpoint of preventing contact betweenthe main body unit 14 and the housing 80.

FIG. 17 illustrates an example in which the buffering member 104 isdisposed in such a way as to cover the entire periphery of the main bodyunit 14. A position of the buffering member 104, however, is not limitedto the position illustrated in this example. For example, the bufferingmember 104 may be disposed only at a part where the main body unit 14 isexpected to come in contact with the housing 80.

A buffering member different from the above gelled buffering member mayalso be used. One or a plurality of resin or metal buffering membershaving a bearing structure may be used as the buffering member 104. Thebuffering member 104 having the bearing structure is made of, forexample, Teflon. FIG. 18 is a side view of the resin or the metalbuffering member 104 having the bearing structure, and FIG. 19 is adiagram of the buffering member 104 of FIG. 18, when seen from the frontside of the moving direction of the piston motion. The buffering member104 is cylindrical and is disposed on the periphery of the main bodyunit 14.

Also, the buffering member 104 may be a resin or a metal ring-shapedmember. In this configuration, the ring-shaped buffering member 104 isdisposed at one or a plurality of places on the periphery of the mainbody unit 14 where the main body unit 14 is expected to come in contactwith the housing 80.

In the example illustrated FIGS. 18 and 19, it is preferable that, toreduce friction between an inner surface of the bearing structure(buffering member 104) and the main body unit 14, a contact surface ofthe buffering member 104 in contact with the main body unit 14 besubjected to the following surface treatment. For example, the contactsurface of the buffering member 104 in contact with the main body unit14 may be subjected to a mirror surface treatment (in the case of themetal buffering member 104, for example, the contact surface may bepolished). Alternatively, the contact surface of the buffering member104 in contact with the main body unit 14 may be subjected to a coatingtreatment. As such coating treatment, for example, silicon coating orTeflon coating is effective.

A plurality of projections may be provided on an inner wall (innersurface) 88 of the housing 80, as the buffering members 104. FIG. 20illustrates a configuration in which eight projecting bars (ribstructures) are provided as the buffering members 104, illustrating aview of the buffering members 104, when seen from the front side of themoving direction of the piston motion of the main body unit 14. FIG. 21is a cross-sectional view when the buffering member 104 of FIG. 20 isdisposed in the measurement apparatus 1. As illustrated in FIG. 20,eight bar-like buffering members 104 are arranged at certain intervalson the periphery of the main body unit 14 (which is indicated by avirtual line). Also, as illustrated in FIG. 21, the eight bar-likebuffering members 104 extend along the direction of the piston motion ofthe main body unit 14.

In an example in FIGS. 20 and 21, an example in which the eight bar-likebuffering members 104 are arranged has been described. The plurality ofprojecting buffering members 104 are effective in such a structure as toreduce a contact area between the housing 80 and the main body unit 14or to reduce a friction coefficient between the housing 80 and the mainbody unit 14.

The plurality of projecting buffering members 104 should be arranged insuch a way as to support the periphery of the main body unit 14(circumference of the main body unit 14) at least three points. Whenrattling arising as a result of the piston motion of the main body unit14 and the movable unit 15 by the crank mechanism is taken intoconsideration, it is preferable that four or more projecting bufferingmembers 104 be arranged on the periphery of the main body unit 14(circumference of the main body unit 14).

In the example of FIG. 20, a section of each of the buffering members104 (i.e., a section of the projection when seen from the front side ofthe moving direction of the piston motion) is rectangular but is notlimited to this. The section of each of the buffering members 104 (i.e.,a section of the projection) may be of other shapes such as a triangularor a semi-spherical shape. Also, since the buffering member 104 has therectangular section and is formed to have the bar-like shape along thedirection of the piston motion of the main body unit 14 in the exampleof FIGS. 20 and 21, the buffering member 104 is in surface contact withthe main body unit 14. The configuration of the buffering member 104,however, is not limited to this. The projecting buffering member 104 maybe in point or line contact with the main body unit 14, depending on itsconfiguration such as the sectional shape of the buffering member 104.The contact surface of the projecting buffering member 104 in contactwith the main body unit 14 may be subjected to the above-describedcoating.

Further, stability when the main body unit 14 and the movable unit 15perform the piston motion by the crank mechanism is taken intoconsideration, and to ensure the stability, the main body unit 14 mayhave the groove portions provided at respective positions correspondingto the buffering members 104. For example, the plurality of grooveportions (rail structures) extending along the direction of the pistonmotion of the main body unit 14 may be provided at the respectivepositions corresponding to the bar-like buffering members 104 on theperiphery of the main body unit 14. According to this configuration, therattling arising as a result of the piston motion of the main body unit14 and the movable unit 15 by the crank mechanism can be prevented moreeffectively.

According to this configuration, even if the lateral movement (rattlingin the housing 80) arises when the main body unit 14 and the movableunit 15 perform the piston motion by the crank mechanism, the bufferingmembers 104 disposed between the main body unit 14 and the housing 80can prevent the main body unit 14 from coming in contact with thehousing 80. Preventing the main body unit 14 from coming in contact withthe housing 80 enables the main body unit 14 and the movable unit 15 toperform smooth piston motion. Accordingly, it is possible to preventnoise from mixing in information from the acceleration sensor 13, and asa result, the accuracy of the hardness measured by the biometricdurometer can be improved.

The present invention is not limited to the above-described embodiments,and various modifications are included. For example, the above-describedembodiments have been described in detail so that the present inventionis easily understood, and are not limited to the one necessarilyincluding all configurations described. Also, a part of theconfiguration of an embodiment can be replaced with the configuration ofother embodiments. Also, the configuration of other embodiments can beadded to the configuration of an embodiment. In addition, otherconfigurations can be added to, deleted from, or replaced with a part ofthe configuration of each embodiment.

A part or all of each processing of the microprocessor 23 describedabove may be realized by hardware, for example, by designing anintegrated circuit. In addition, each configuration, function, etc.described above may be realized by software in which a processorinterprets and executes a program realizing each function.

Information such as a program realizing each function, a table, and afile may be stored on a recording device such as a memory, a hard disk,or a solid state drive (SSD), or a recording medium such as an IC card,an SD card, or a DVD.

A control line or an information line considered to be necessary fordescription is indicated in the above-described embodiments, and all thecontrol lines or the information lines in the product are notnecessarily indicated. All configurations may be mutually connected.

EXPLANATION OF REFERENCE CHARACTERS

-   -   1000 . . . Biometric durometer    -   1, 1 a . . . Measurement apparatus    -   2 . . . Hardness calculation apparatus    -   11 . . . Receiving coil    -   12 . . . Transmitting coil    -   13 . . . Acceleration sensor (first sensor)    -   14 . . . Main body unit    -   15 . . . Movable unit    -   16, 16 a . . . Spring    -   17(a) . . . Spring    -   17(b) Dashpot    -   18 . . . Battery    -   19 . . . Magnetic sensor (second sensor)    -   20 . . . Contact portion    -   21, 22 . . . Driving circuit    -   23 . . . Microprocessor    -   24 . . . Storage unit    -   25 . . . Sound generation unit    -   26 . . . Display unit    -   27 . . . Power source unit    -   28 . . . Input unit    -   31 . . . AC oscillation source    -   32 . . . Amplifier    -   33 . . . Preamplifier    -   34 . . . Detection circuit    -   35 . . . Reference signal    -   36 . . . Low-pass filter    -   80 . . . Housing    -   81 . . . Motor    -   82 . . . Crank shaft    -   83 . . . Bearing member    -   84 . . . Link    -   85 . . . Connecting member    -   86 . . . First member of the main body unit    -   87 . . . Second member of the main body unit    -   91 . . . First member of the movable unit    -   92 . . . Second member of the movable unit    -   93 . . . Buffering member    -   94 . . . Antislip member    -   95, 96 . . . Groove portion    -   101 . . . Contact member    -   101 a . . . Press portion    -   102 . . . Cutout    -   104 . . . Buffering member    -   110, 120 . . . Coil board    -   130 . . . Operating circuit board    -   190 . . . Operation button    -   231 . . . Differential waveform generation unit    -   232 . . . Waveform comparison unit    -   233 . . . Conversion coefficient calculation unit    -   235 . . . Calculation unit    -   236 . . . Determination unit

1. A durometer comprising: a movable unit pressed continuously againstan object to be measured; a main body unit connected to the movable unitvia a resilient member; a housing the main body unit; and a drivingmechanism driven by a motor and causing the main body unit and themovable unit to perform piston motion with respect to the main housing,wherein the movable unit and the main body unit are respectivelyprovided with a coil disposed to be opposed to each other, the coilsbeing configured such that reactive force information corresponding to areactive force at a contact part of the object to be measured in contactwith the movable unit is output.
 2. The durometer according to claim 1,further comprising: a contact member having a shape so as to encircle aperiphery of the movable unit and in contact with the object to bemeasured, wherein the contact member includes a cutout.
 3. The durometeraccording to claim 2, wherein the contact member is of a cylindricalshape, and the cutout occupies ½ or more of a circumference of thecontact member when seen from a side of a contact surface in contactwith the object to be measured.
 4. The durometer according to claim 1,wherein the driving mechanism is a crank mechanism.
 5. The durometeraccording to claim 4, wherein the crank mechanism includes: a crankshaft located eccentric to a shaft of the motor; and a connecting memberconnecting the crank shaft to the main body unit, wherein a length ofthe connecting member is ⅓ or more of a length of the main body unit ina moving direction.